Copending U.S. patent application of Larry D. Bronson and myself, Ser. No. 122,457, filed Feb. 19, 1980 on a Portable Crushing and Screening Plant, shows a screening device fed by a belt elevator which is foldable from an upright elevated operating position to a lowered, folded transport position by a first hydraulic power means and shows a screening device which is lowered from an elevated operating position to a lowered transport position by a second hydraulic power means. U.S. Pat. No. 3,439,806, Apr. 22, 1969, issued to R. A. Kass et al on a Portable Screening Plant shows a screening device pivoted at one end for swinging movement from a lowered transport position to an elevated operating position. The screening device in the Kass et al patent includes an underlying, inclined belt conveyor for receiving screened material. The inclined belt conveyor of the Kass et al patent has a first support frame fixedly secured to the screen frame and a second support frame hinged at one end to the first support frame and supported at its other end by a support link.
It is a primary object of the present invention to provide an improved portable crushing and screening plant, wherein an elevatable screen and a foldable elevator section of a belt conveyor are interconnected for simultaneous raising and lowering. It is also an object of the present invention to provide an improved belt conveyor apparatus in a portable crushing and screening plant.